1. Field of The Invention
The present invention relates generally to a vehicle performance/safety enhancing system. More particularly, the invention is directed to an integrated control system for controlling operations of an electronic torque-split system and a traction control system.
2. Description of The Prior Art
Japanese Patent First Publication (tokkai) No. 4-103847 discloses a conventional integrated control system for an electronic torque split system and a traction control system incorporated in a 4WD vehicle. This system is adapted to project a road surface friction coefficient when wheelspin occurs at all four wheels while engine torque is delivered to front wheels and to reduce the driving torque of the wheels based on the projected value, thereby restricting the wheelspin to improve accelerating and cornering stabilities.
In the above prior art control system, whether the vehicle is traveling straight or cornering, the occurrence of four-wheel wheelspin is constantly monitored for traction control. Therefore, there is no problem when the vehicle travels straight. However, when the four-wheel wheelspin is created during cornering, engine torque is reduced only after cornering forces of the front wheels have been decreased greatly with the result that the vehicle is subject to understeering prior to the reduction in engine torque under the traction control.